Garth Hammers, specialist at auction house Gooding & Company, said "Today, some 60 years on, it is almost impossible to find another pair of 300 SLs still in their original family ownership and unrestored.

"I think collectors are going to be very excited to see these two particular cars come to auction at Pebble Beach."

Gooding & Company will be selling both cars at its high-profile Pebble Beach sale in California over the weekend of August 18.